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123I-radiolabeled metaiodobenzylguanidine (123I-MIBG) cardiac imaging has been used to evaluate the distribution of sympathetic nervous system (SNS) in the heart. Different heart diseases have shown impaired cardiac SNS distribution as reflected by MIBG activity. The aim of this study was to assess the cardiac distribution of SNS in normal subjects, using MIBG imaging. Ten normal subjects (1 male and 9 females, mean age 46 +/- 9 years) with no cardiac abnormalities underwent myocardial 123I-MIBG scintigraphy, Tc-99m methoxyisobutylisonitrile (MIBI) cardiac perfusion imaging and equilibrium radionuclide angiography (RNA). Regional myocardial MIBG and MIBI activities were quantitatively evaluated using a region of interest analysis. For this purpose, the left ventricle was divided into 6 myocardial regions as anterior, apical, inferior, septum, lateral and posterolateral. In particular, myocardial MIBG and MIBI activities were measured as myocardium to mediastinum ratio. Regional left ventricular function was assessed by RNA. Myocardial MIBG uptake was homogeneous in anterior (2.2 +/- 0.5), inferior (2.5 +/- 0.7), septal (2.4 +/- 0.4), lateral (2.3 +/- 0.4), and posterolateral (2.3 +/- 0.4) regions. Conversely, MIBG uptake was significantly lower in the apical region (1.9 +/- 0.3) compared to all other left ventricular segments (p < 0.05). Regional myocardial perfusion, as measured by MIBI uptake, was homogeneous in all regions. No regional left ventricular wall motion abnormalities were observed by RNA. In conclusion, our data suggest that a decreased MIBG uptake may be observed in the left ventricular apical region of normal subjects reflecting reduced sympathetic innervation of the apex. This finding is not related to myocardial perfusion or wall motion abnormalities. The knowledge of cardiac sympathetic innervation in normal subjects may be helpful to assess SNS abnormalities in heart disease.

Introduction: The clinical applications of fluorine-18-deoxyglucose Positron Emission Tomography (FDG PET) have been proposed on account of experimental evidence of increased glucose metabolism in tumor cells., Material and Methods: We examined 98 lymphoma patients--33 with Hodgkin and 65 with non-Hodgkin disease--with FDG PET and compared its findings with those of clinical and conventional radiologic studies. FDG PET was also used to follow-up 32 patients and the results were once again compared with clinical and radiologic data., Results: During staging, 138 lesions were found, 82 of them (59%) in nodal and 56 (41%) in extranodal locations. Extranodal tumor sites were found in 39 patients (40%), namely 4 with Hodgkin (12%) and 35 with non-Hodgkin (54%) disease. FDG PET findings were in agreement with clinical and radiologic results in all nodal and extranodal lesions, since all of them exhibited abnormally increased FDG uptake. PET detected new tumor sites in 6 patients. In the follow-up, agreement was observed in the majority (78%) of lesions, 30 of them in complete regression, 15 in partial regression and 17 in progression; however, the diagnostic results were in disagreement in the remaining (22%) tumor sites: no abnormal FDG uptake was found in 9 cases despite the persistence of radiologic abnormalities (post-treatment fibrosclerosis). Slightly increased FDG uptake (residual disease) was found in the other 8 lesions, where there was no clinical and/or radiologic evidence of disease., Conclusions: FDG PET is a functional imaging technique useful to diagnose lymphomas and providing metabolic characterization of cancer abnormalities. Whole body PET permits the simultaneous assessment of nodal and extranodal lymphoma localizations. During the follow-up, FDG PET permits better monitoring of treatment effects than clinical and radiologic examinations.

In this study, 15 patients (4 men and 11 women, mean age: 50 +/- 13 years) with unilateral adrenal masses detected on ultrasound (US), Computed Tomography (CT) and/or Magnetic Resonance (MR) studies were submitted to positron emission tomography (PET) with fluorine-18 deoxyglucose (FDG). Histology demonstrated 3 adenomas, 1 myelolipoma, 1 angiolipoma, 1 neurinoma, 1 cyst, 1 malignant pheochromocytoma, 4 carcinomas and 3 metastases. The patient population was divided into two groups. Group 1 (n = 7) consisted of benign adrenal lesions. Group 2 consisted of malignant adrenal tumors. Lesion measurements were performed on the basis of the results of US, CT and/or MR images. In Group 1, no FDG uptake was observed in adrenal masses. Conversely, in Group 2 adrenal lesions showed abnormally increased FDG uptake, suggesting high glucose tumor metabolism. No significant difference in lesion size was observed between Groups 1 and 2 (5.6 +/- 4.0 vs 6.3 +/- 3.0 cm). Furthermore, in 6 patients of Group 2, total body PET images showed abnormal FDG uptake in extra-adrenal locations, such as chest (n = 2) and abdominal (n = 5) lymph nodes, lungs (n = 6), liver (n = 5), pancreas (n = 1), bone (n = 1) and muscle (n = 1) tissues. In conclusion, the results of this study suggest that PET imaging with FDG can characterize adrenal masses. In particular, abnormally increased FDG uptake in adrenal malignancies allows to differentiate these abnormalities from benign lesions. Furthermore, total body imaging PET can identify extra-adrenal tumor sites in patients with malignant tumors.

In this study, 35 patients (11 men and 24 women, mean age 47 +/- 16 years) with unilateral adrenal masses underwent nor-cholesterol (nor-Chol) (n = 11), metaiodobenzylguanidine (MIBG) (n = 15) or nor-Chol and MIBG (n = 9) radionuclide studies. In all patients Magnetic Resonance (MR) adrenal imaging was also performed. In 19 (54%) patients, no laboratory abnormalities of adrenal function were observed. In the other 16 (46%) patients, adrenal hyperfunction was found. In 21 lesions, histology showed 10 pheochromocytomas (Pheos), 6 adenomas, 3 metastases, 1 cyst and 1 nodular focal liver hyperplasia. In the remaining 14 lesions, increased cortisol (n = 4) or aldosterone (n = 2) levels and/or intense nor-Chol uptake (n = 14) were considered suggestive of adenoma. Diagnostic accuracy of both nor-Chol and MIBG radionuclide studies in correctly identifying adenoma or Pheos was 100%. Conversely, qualitative MR signal intensity (SI) analysis on T2-weighted images did not allow to accurately distinguish lesions of different nature. In particular, 10 Pheos, 8 adenomas, 3 mestastasis and 1 cyst clearly showed on T2-weighted images higher SI than the liver; 5 adenomas had a slight higher SI; the remaining lesions (7 adenomas and 1 liver hyperplasia) exhibited low SI. In conclusion, adrenal scintigraphy using nor-Chol or MIBG allows to identify adenomas and Pheos, respectively. Conversely, qualitative MR SI analysis cannot differentiate different adrenal lesion (Pheos, adenoma, metastasis and cyst) and yields heterogeneous results in adenomas.

P280, a synthetic peptide composed of 26 aminoacids, has high affinity (Kd = 100 nM) and specificity for the glycoprotein IIb/IIIa (GPIIb/IIIa) receptor expressed on activated platelets. In this study we investigated the potential usefulness of imaging deep vein thrombosis (DVT) and pulmonary embolism (PE) in humans with 99mTc-P280. In 15 patients (9 men and 6 women; mean age +/- s.d.: 49.2 +/- 14.1) with known DVT and/or PE, serial images were acquired within 24 hours of the injection of approximately 200 micrograms of P280 radiolabelled with 10-23 mCi of 99mTc. P280 was labelled with the ligand exchange method using 99mTc-glucoheptonate. Rapid blood clearance (< or = 5% ID was still circulating in 1 hour) enabled identification of thrombi as early as 60 minutes after the injection, with significant thrombi-to-background ratios (range: 2-4) in 11/15 patients (73%), in 7/9 with DVT, in 2/3 with PE and in 2/3 patients with both DVT and PE. Radiotracer uptake was clearly detectable also in late scans, which confirms that 99mTc-P280 specifically binds to the thrombi through a receptor-mediated mechanism. PE localizations were detectable 3-4 hours after peptide injection, and in 2 cases SPECT enabled the detection of thrombi missed on planar views. Conversely, the test was negative in 4 patients who had the onset of clinical symptoms and the diagnosis of DVT and/or PE more than 40 days before scintigraphy. The lack of 99mTc-P280 uptake in the latter patients suggested that the peptide does not bind to thrombi when thrombogenesis is not active. These preliminary results clearly indicate scintigraphy with 99mTc-P280 to be a suitable, noninvasive and highly specific tool to image fresh clots causing DVT and/or PE. Thus, this technique might overcome the limitations of the imaging procedures currently in use.